Carbon (C)

Carbon is a chemical element with an atomic number of 6  in the periodic table of elements. It’s the 19th most abundant element found in nature. With a quantity of approximately 0.025 percent in Earth’s crust (2.00×102 milligrams per kilogram), carbon is not really plentiful.

However, it is widespread and it’s one of the chemical elements that form numerous compounds. Despite being relatively unreactive, this member of the carbon family has four valence electrons that help carbon make numerous compounds with many non-metal elements of the periodic system. 

Chemical and Physical Properties of Carbon

Symbol of CarbonC
Atomic number6
Group of CarbonNon-Metal
Crystal Structure of CarbonHexagonal
Atomic weight (mass)12.011
Shells of Carbon2,4
Orbitals of Carbon[He] 2s2 2p2
Valence of Carbon2,3,4
ColorIt depends on the carbon allomorph (the colors palette includes the following nuances: transparent/colorless, white, black and shiny, dark brown, or black)
Physical stateSolid non-metal at room temperature
Electronegativity according to Pauling2.55
Density2.62 g/cm³
Melting point3920
Boiling point5100.15
Van der Waals radius170 pm
Ionic radius.16 (+4) Å
Covalent Radius of Carbon0.77 Å
Atomic Radius of Carbon0.91 Å
Atomic Volume of Carbon04.58 cm³/mol
Name Origin of CarbonLatin: carbo, (charcoal)
Discovered ByKnown to the ancients
Pronounced of CarbonKAR-ben
Oxydation States of Carbon(±4),2
Uses of CarbonFor making steel, in filters, and many more uses. Radiocarbon dating uses the carbon-14 isotope to date old objects
Description of CarbonColorless, odorless, tasteless, generally inert gas. Fifth most abundant element in the universe. Makes up about 78% of earth’s atmosphere

This star-born substance has the periodic table symbol C, atomic number 6, variable atomic mass from 12.0096 to 12.0116 g.mol -1, and electronic configuration [He] 2s2 2p2. Carbon is a polyatomic nonmetal with a hexagonal crystal structure that reaches its boiling point at 4827 °C, or 5100 K (8721 °F). With a melting temperature of 3500 °C (3773 K, 6332 °F), carbon has the highest melting point among the periodic system elements.

With oxidation states of +2, +3, +4, and the highest sublimation point among all elements, carbon has an electronegativity of 2.55 according to Pauling, whereas the atomic radius according to van der Waals is 170 pm. However, both the chemical and physical properties of carbon depend on its allotropic structure, which makes it one of the most unique and versatile chemical elements.

This tetravalent member of the carbon family of elements in the periodic table is able to form covalent chemical bonds. Carbon is an excellent conductor of electricity, possesses great thermo-insulating properties, and is extremely durable. When exposed to high temperatures, carbon burns brightly. It can be dissolved by acids and bases, but it’s insoluble in water.                         

How Was Carbon Discovered?

Charcoal and soot were familiar to the ancient civilizations way before our times. They used coal to start fires. But, despite the fact of carbon being discovered far before the times of modern chemistry, many chemists have attempted to determine both the chemical and physical properties of carbon by studying and experimenting with its various forms and compounds in much more recent times. 

In the 17th century, the Anglo-Irish chemist Robert Boyle (01.25.1627 – 12.31.1691) was the first scientist who discovered carbon as an element that cannot be further broken down into other substances. In 1694, the Florence based naturalists Giuseppe Averani and Cipriano Targioni experimented with directing sunlight to a diamond via a magnifying glass. The result gave them supported evidence that heat can destroy the diamond. In their case, the diamond had disappeared under the heat of sunlight. 

In 1772, the French nobleman and chemist Antoine-Laurent de Lavoisier (or simply: Antoine Lavoisier), who is considered as the ‘father of modern chemistry’, attempted an experiment in order to prove that the diamond is an allotrope of carbon. In 1789, he published his findings of the new element of the periodic table.

His findings were enriched by the finding of the German chemist Carl Wilhelm Scheele. Namely, in 1779 he additionally discovered that graphite was also a carbon allotrope, which completed the information of carbon as a chemical element. 

In 1797, the British chemist Smithson Tennant performed a series of experiments that provided him with sufficient evidence that diamond is a pure form of carbon and that the carbon dioxide compound is made only of carbon and oxygen.  

How Did Carbon Get Its Name?

The Latin word for burnt wood, “carbo”, was used in labelling this chemical element. This term refers to one of the naturally occurring impure forms of carbon (coal) formed by the burning of wood. 

Where Can You Find Carbon?

According to the Swinburne Center for Astrophysics and Supercomputing, carbon is formed in the core of stars by the triple-alpha process. This chemical substance is released after leftover helium burns in the older stars. In Earth’s atmosphere, carbon is found in the form of carbon dioxide (CO2). In nature, carbon can be found in coal, methane clathrates, peat, and fossil fuels. Carbon monoxide (CO) can be obtained from the exposure of fossil fuels to extremely high temperatures.

In its pure crystal form, carbon occurs as graphite and diamond in nature. However, in order to get their commercial form, these carbon allotropes first must be processed. With an accumulation of 18.5 percent, carbon is also the second most abundant trace element in the human body.

Carbon in Everyday Life

Carbon and its alloforms (fullerene, diamond, graphite, coal) have wide use in everyday life and many industries. For example, carbon in all its forms can be applied for making plastics from carbon polymers, in the production of charcoal (an impure carbon made of wood), as a major source of fuel, in steel production, as a gas absorber, for making nuclear reactors, for metal smelting, in the production of dry batteries, as an addition to ink for printers, as pencil tips, a bleaching agent, in the making of precious jewellery, for electro-forming and electroplating, etc.  

Organic Macromolecules and Carbon 

Since carbon is present in almost all forms of life, it is naturally found in the food we consume, too. Namely, fats, carbohydrates, proteins, and nucleic acids, are groups of organic macromolecules that contain carbon atoms as a mutual constitutional element. 


Fats are molecules made up of carbon and hydrogen atoms. Due to the molecular carbon chain in the fats, they cannot be dissolved in water (just like carbon itself). American diet mainly consists of saturated fats, such as red meat, bacon, whole-milk dairy products, lard, butter, etc. The term ‘saturated’ is used to label the number of hydrogen atoms gathered around an atom of carbon.  

However, despite being tasty, a long-term diet rich in saturated fats can lead to raised levels of cholesterol and eventually result in chronic heart disease

Carbohydrates and Cellulose 

Carbohydrates are composed of carbon, hydrogen, and oxygen; they even contain carbon in the name. Cellulose is a form of carbohydrate which is found in this group. It’s one of the most abundant carbohydrates that are found in nature. When we consume foods rich in cellulose, such as leafy green vegetables, fruit (apples, pears), grains, and vegetables, we feel fuller much faster.

Even though our body is unable to process cellulose, it’s very important that it’s included in our diet due to its laxative properties that eliminate toxins, regulate blood sugar levels, and improve the metabolic function of our body. 


Found in dairy products, meat, legumes, and nuts, proteins consist of molecular chains made up of carbon and amino acids. Proteins are highly important for the proper functioning of the cellular mechanisms which, in turn, builds the immunological defense of our body. They also serve as the building blocks of our hair, nails, muscles, and ligaments. 

Nucleic Acids

Nucleic acids are molecule chains of carbon atoms and nucleotides. They comprise an essential part of our DNA and RNA molecules that house the genetic information. The proper functioning of the cellular mechanisms of these molecules is directly responsible for the bodily functions and homeostatic processes. 

Fossil Fuels

Fossil fuels release extremely large amounts of carbon by burning. Coal, crude oil (petroleum), lignite, and natural gas (methane), are naturally found carbon compounds that are extracted from the fossil fuel deposits in the oceans, accumulated under layers of sand and mud.

Natural gas is formed by an application of great pressure and heat over a period of time longer than it takes for the natural oil to be formed. On the other hand, the petrification of trees and plants as a result of heat and pressure in the deeper layers of Earth’s crust results in the formation of coal. 

Today, fossil fuels based on carbon comprise the world’s most dominant source of energy. By producing almost 20% of all quantities of fossil fuels around the globe, the United States is the largest fossil fuel and natural gas producer. Venezuela, Russia, Iran, and Canada also take place on the list of the world’s biggest fossil fuel and natural gas producers. On the other hand, China is the world’s biggest producer of coal among the coal-producing countries.

How Dangerous Is Carbon?

In its elemental form, carbon is almost a non-toxic substance. However, some of its forms can be extremely lethal. Such are carbon monoxide, cyanide, and tetrodotoxin.

Carbon Monoxide (CO)

Carbon monoxide (CO) is an odorless and colorless highly flammable gas that can be extremely dangerous health-wise. Namely, by binding to the hemoglobin molecules in blood, this form of carbon depletes the organism from its most essential element – oxygen. This deteriorates the function of all tissues and organs of the body due to a lack of oxygen supply. 

Carbon monoxide poisoning occurs upon exposure to high levels of this gas in a closed space via car exhaust fumes or burning fuel… When inhaled, instead of oxygen, it’s absorbed by the red blood cells, which inflicts damage to the lungs and the tissues of the body. Some of the symptoms of carbon monoxide poisoning include dizziness, headache, nausea, loss of consciousness, and even death. 

Cyanide (CN-)

Cyanide (CN-) is a simple carbon compound made up of one carbon and one hydrogen atom, linked together with a triple bond. However simple the compound, the substance has extremely toxic properties. Cyanide poisoning mainly occurs as a result of inhalation of industrial fumes, or via consumption of cyanide contaminated food or water. Clinically, cyanide poisoning manifests as an irritation of the breathing passages, and heart failure that swiftly leads to a fatal outcome.

Tetrodotoxin (C₁₁H₁₇N₃O₈)

Tetrodotoxin is a highly lethal biotoxin, associated with the Vibrio alginolyticus and  Pseudoalteromonas tetraodonis bacteria that is carried by the Tetraodontiformes family of fish (such as the pufferfish), crabs, newts, some frogs, etc. Made of 11 carbon atoms, 17 hydrogen atoms, 3 nitrogen atoms, and 8 Oxygen atoms, this neurotoxin blocks the sodium channels located in the membrane of the neuron cells. In this way, tetrodotoxin inhibits the relay of sensory information between the neurons. 

After consummation of some of the aforementioned fish or marine animals, the symptoms experienced by the individual affected by this neurotoxin include paralysis, neurological problems, tingling, numbness of the mouth, fingers or extremities, gastrointestinal problems, etc. 

Environmental Effects of Carbon

The elemental form of carbon has no negative environmental effects. However, the effects of some of its compounds extend from the environmentally most beneficial (photosynthesis) to most detrimental for the environment (the greenhouse effect). 

The Carbon Cycle (Photosynthesis)

Antoine Lavoisier and Joseph Priestley were the first naturalists who detected the carbon cycle, which was later more thoroughly studied by Sir Humphry Davy. The carbon cycle is the fluctuation of this star-made substance through the geosphere, biosphere, hydrosphere, pedosphere, and atmosphere of Earth. The consistency of the carbon cycle supports the formation of other carbon compounds and many biological processes that are of vital importance. 

One of the most important influences of the carbon cycle is photosynthesis – a process that enables the existence of oxygen in the atmosphere. During the process of photosynthesis, plants and trees absorb the toxic carbon dioxide that has been released into the air. By carbon sequestration, the plants remove carbon dioxide from the air in order to use it for the production of glucose, which is their energy source.  After that, they release pure oxygen back, thus purifying the air.

Carbon Dioxide (CO2 – The Greenhouse Gas)

Carbon dioxide is a colorless and odorless gas with an unpleasant, sharp smell. It’s released by the burning of carbon compounds, but also by people and animals via respiration. Namely, when we inhale oxygen, we exhale carbon dioxide. In the 17th century, the Belgian chemist Jan Baptista van Helmont was the first scientist who observed carbon dioxide as a resulting substance from the burning of fuels. 

Despite being an essential element for the health of plants, the increased levels of atmospheric carbon dioxide lead to severe climate change by raising the natural temperatures of the seasons. Together with water vapor, methane, and nitrous oxide, carbon dioxide is considered as one of the greenhouse gasses.

Namely, these gases lead to global warming, causing the ‘greenhouse’ effect that disrupts the normal cycles in nature by absorbing the warmth of the Sun and reverting it back to Earth. As a result, the millennium-old ice glaciers melt, animals lose their natural habitats, many animal and plant species become extinct. Nature and people suffer. 

What is a Carbon Footprint?

The amount of carbon emissions in the atmosphere is known as a carbon footprint. It’s a result of the increased traffic and exhaust fumes from transport (cars and planes), heating, industrial chimneys, and use of various natural fuel-consuming services. 

How to Reduce the Greenhouse Effect and Global Warming?

Climate change is an inevitable fact that our planet (as well as our life on the planet) is endangered mainly by our quest for more natural goods. The fossil fuels exploitation, cutting of the forests, increased work of the industries, pollution of waters and air, cities clogged with traffic – these are only a few of the triggers for the greenhouse effect, extinction of animals, and rapid temperature fluctuations.

In order to reduce the negative greenhouse effect and global warming, we could try and implement some simple things in our everyday life:

  1. Use bicycles or walk, instead of driving cars that pollute the air;
  2. Reduce, reuse, recycle;
  3. Find a natural substitute for plastic products;
  4. Use the energy resources wisely;
  5. Spare electric energy and water;
  6. Use alternative ways of heating instead of electric energy;
  7. Use energy-saving LED bulbs instead of the regular ones;
  8. Plant trees (the more, the better);
  9. Limit waste. 

Isotopes of Carbon

With a half-life of 5730 years, the 14C is the longest-living carbon isotope. It’s mainly used in radiocarbon dating and radiolabeling. 

Nuclide[2]ZNIsotopic mass (Da)[3]


[n 1]



[resonance width]




[n 2]




[n 3]

Spin and



[n 4][n 5]

Natural abundance (mole fraction)
Normal proportionRange of variation
8C628.037643(20)3.5(1.4) × 10−21 s


[230(50) keV]




[n 6]

9C639.0310372(23)126.5(9) msβ+, p (61.6%)8



[n 7]

β+, α (38.4%)5



[n 8]

10C6410.01685322(8)19.3009(17) sβ+10



11C[n 9]6511.01143260(6)20.364(14) minβ+ (99.79%)11



EC (0.21%)[4][5]11



12C6612 exactly[n 10]Stable0+0.9893(8)0.98853–0.99037
13C[n 11]6713.00335483521(23)Stable1/2−0.0107(8)0.00963–0.01147
14C[n 12]6814.003241988(4)5,730 yearsβ14



0+Trace[n 13]<10−12
15C6915.0105993(9)2.449(5) sβ15



16C61016.014701(4)0.747(8) sβ, n (97.9%)15



β (2.1%)16



17C61117.022579(19)193(5) msβ (71.6%)17



β, n (28.4%)16



18C61218.02675(3)92(2) msβ (68.5%)18



β, n (31.5%)17



19C[n 14]61319.03480(11)46.2(23) msβ, n (47.0%)18



β (46.0%)19



β, 2n (7%)17



20C61420.04026(25)16(3) ms


[14(+6-5) ms]

β, n (70%)19



β (30%)20



21C61521.04900(64)#<30 nsn20



22C[n 15]61622.05755(25)6.2(13) ms


[6.1(+14-12) ms]





Source: Wikipedia

Carbon Compounds 

Carbon compounds make the basis of all life-forms found on our planet Earth. The list of carbon compounds is one of the most extensive among the chemical elements of the periodic table. For instance, carbon compounds form some of the most exploited minerals, such as magnesite, dolomite, gypsum, marble, or limestone. Among them, methane (CH4) is the most simple carbon compound.

Hydrogen is the only chemical element that forms more compounds than carbon. Hence, the largest number of carbon compounds contain both hydrogen and carbon, forming the organic compounds labeled as hydrocarbons (natural gas, crude oil, oil shales, coal, etc.). These hydrocarbons are mainly used as fuels. 

When combined with oxygen (O2), carbon forms the following gaseous substances: carbon monoxide CO, carbon dioxide CO2, and carbon suboxide C3O2.

Allotropes of Carbon 

The distinct forms of carbon include: 

  • Graphite; 
  • Diamond; 
  • Fullerene; 
  • Graphene;
  • Amorphous carbon.


Being one of the softest natural materials, graphite (also: plumbago, blacklead, or mineral carbon) is the hexagonal crystal form of carbon. This mineral is very soft but resistant to high temperatures. It’s found in the natural deposits that were exposed to pressure and heat, resulting in the formation of gneiss, marble, and schist, from which graphite is extracted. New York and Texas are the U.S. location where the largest deposits of graphite are found. 

The most popular use of this carbon mineral is probably as a lead in pencils. Hence, the Greek word “graphite”, denoting ‘to write’, has been used to label this carbon allomorph. In addition, the wide use of graphite encompasses its application in the steelmaking industry, manufacture of batteries, etc.


Diamond is the hardest natural gem-quality allomorph of all periodic table elements and the only precious gem that has been formed by a single chemical element. Its formula is simply labeled with the symbol of carbon – (C). It is formed in the deep Earth layers under high pressure and temperature but can be found as shallow as the river beds.

The lamproite and the soft bluish peridot rock labeled as kimberlite (referring to the famous deposit at Kimberley, South Africa) are the main sources of diamonds. Some traces of diamonds are also found in the meteorites. Since ancient times, diamonds have been considered gemstones of prestige and wealth. 


This carbon allotrope was discovered in 1985, by the research team of Rice University in Texas, led by Rick Smalley and Robert Curl. Their attempt to vaporize graphite using a laser resulted in a new form of carbon, labeled as buckminsterfullerene. Or more simply – carbon nanotubes and buckyballs.

Fullerene is used in the production of plastic when mixed with atoms of oxygen and nitrogen. In combination with steel, fullerene forms carbon steel. According to the American Iron and Steel Institute (AISI), this alloy does not require an addition of any other element in order to achieve the projected effect. 

What’s more important about fullerene is its application in medicine. According to a study published in 1996, these new pure carbon molecules, i.e. buckyballs, have an inhibitory property regarding the spread of the HIV virus. Medical researchers are currently trying to attach molecules of medicine to the buckyballs so that they can deliver medicine directly to the infection or tumor-affected tissues in the body. 


Graphene is a material made from carbon and has been assigned some superb properties by its researchers. Namely, it’s stronger than steel, thinner than paper, and more flexible than rubber. This carbon allotrope is applied in the manufacture of sensors, precision gadgets, electronics, solar panels, etc. 

Amorphous Carbon

Amorphous carbon is a free form of carbon that has no crystal form. It’s often associated with the impure forms of carbon, such as coal or sooth (lampblack). According to the degree of graphitization, this carbon allomorph can be classified as soft (graphitizable carbon) or hard carbon. 

5 Interesting Facts and Explanations

  1. Carbon occurs in a larger variety of forms than any other of the periodic table elements. 
  2. There are 3.5 times more carbon atoms in the Universe than silicon atoms. 
  3. The chemical elements neon, hydrogen, helium, oxygen, and nitrogen are the only substances that are more plentiful in the Universe than carbon. 
  4. According to the 2009 study in the Journal of Archaeological Science, the most famous corpse in history found frozen in the Alps, Ötzi the Iceman, had tattoos on his body that were probably made with carbon, taken from the fireplace soot. 
  5. Cows pollute the air nearly as much as cars. This can be explained by the fact that when these ruminant animals regurgitate the cud, their stomachs become saturated with methane-producing bacteria. Later, the cows belch out the methane into the air which significantly adds to the quantity of greenhouse gasses. This is also one of the reasons why cow’s excreta is used for the production of eco-fuels.